The present invention generally relates to the field of portable generators, and more particularly to a full power selector switch for portable generators for allowing a user to switch off the 240 volt output of the generator so that it may provide additional 120 volt power.
Portable generators are typically designed to be compatible with the utility supplied power systems that serve most residential buildings. Thus, the power from the generator can be safely applied during a utility outage through a transfer switch. To maintain the correct electrical supply in the United States, the output of the alternator is connected such that there are two 240 VAC power leads in addition to a neutral lead. This provides the user with the choice of using either 240 volts or 120 volts in any combination up to the limit of the generator.
Because portable generators produce a limited amount of power ( i.e., limited wattage), it is often desirable to optimize the amount of power available for a larger 120 volt load or for a load having a large surge wattage. Such loads may be encountered, for instance, when a 120 volt induction motor being powered by the generator is started and operated. Consequently, portable generators often employ a xe2x80x9cfull power switchxe2x80x9d which allows a user to switch off the 240 volt output in order to get more 120 volt power from the generator thereby improving the generator""s ability to power larger 120 volt loads and to sustain 120 volt surge loads. When full power is selected, the alternator output is reconnected so that the windings are coupled together to additively produce 120 volts while making 240 volt output unavailable.
While it is advantageous to provide users with the option of switching off the 240 volt output of the generator in order to get more power for large 120 volt loads, it has been discovered that users often do not use the feature properly, thereby diminishing the utility of the generator. For example, a user may fail to select the full power switch when a large 120 volt load is to be supplied, such as when an induction motor is started, or, conversely, may fail to deselect the full power switch when 240 volt power is required. Further, since only half of the 240 volt outlet is energized to 120 VAC, failure to disconnect a plug inserted in the outlet can cause unsafe conditions or damaged equipment.
In the past, portable generator manufacturers have attempted to explain proper use of the full power switch through labeling of the panel on which the switch is mounted. However, such labeling has been found to be inadequate to adequately compensate for user error. Consequently, it would be advantageous to provide a full power switch assembly for a portable generator that is capable of instantly communicating the presence and operation of the full power switch to the user. Further, it is desirable to provide a mechanical interlock for the full power switch that requires the user to disengage all plugs from the generator""s 240 volt outlet when full power is selected, since 240 volt power would be unavailable.
Accordingly, the present invention is directed to a full power switch assembly for a portable generator that is capable of instantly communicating the presence and operation of a full power switch to the user. The full power switch assembly includes a first outlet for supplying electrical power having a first voltage (e.g., 120 VAC), a second outlet for supplying electrical power having a second voltage (e.g., 240 VAC), and a switch including a selector. The selector is movable from a first position to a second position for causing the first outlet to be capable of supplying electrical power up to a maximum power level. Movement of the selector between the first position and the second position further causes indicia to be displayed for indicating whether the first outlet is capable of supplying electrical power up to the maximum power level. In exemplary embodiments of the invention, the selector includes a mechanical interlock for preventing a plug from being received by the second outlet when the selector is in the second position.
It is to be understood that both the forgoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention and together with the general description, serve to explain the principles of the invention.